Gee, I hope your hard drive keeps spinning, or you'll have a mess on your hands. I think I take the opposite approach. I try to have the most easy-to-reproduce dev (and just general use) environment possible.
Unless I am doing very heavy weight development work all of my dev envs are in VMware Worktstation virtual machines. So flexible to work with and I can archive off the whole devenv with the project once complete knowing I can just load it back up in a few minutes if I need to in the future. Bliss.
Same here. So if my tower blows up for whatever reason, I can be up and running by installing VMware and loading my basic environment image from a backup. Pull down the latest code and I'm good to go.